Daikin VRV W T-Series Installation Manual

Also see for RWEQ120TAYCU: Operation manual Installation manual

Contents

4 PreparationInstallation manual17RWEQ96~432TAYCUVRV W T-Series water-cooled system air conditioner4P540122-1B – 2018.114 4 3 Maintenance of plate-type/brazed plateheat exchangerCAUTIONA brazed plate-type heat exchanger is used for this unit.Because its structure is different from a conventional typeheat exchanger, it must be handled in a different manner.When designing the equipment1 Install a strainer (standard accessory) at the water inlet sideadjacent to the outside unit in order to prevent any foreignmaterials such as dust, sand, etc. from entering.2 Depending on the water quality, scale may stick to the plate-type heat exchanger. In order to remove scale, it is necessaryto use chemicals to clean it at regular intervals. To this end,install a gate valve in the water piping. Set up a pipingconnection port on the piping between this gate valve and theoutside unit for cleaning by chemicals.3 For the purpose of cleaning and water drain-off from the outsideunit (water draining during a long period of non-use in winter,draining upon starting of season-off), install an "air dischargevalve" and a "water draining plug" at the inlet/outlet ports ofwater piping. In addition, install an "automatic air dischargingvalve" at the top of riser piping or at the top of a portion whereair tends to stay.4 Independent of the piping inlet of the outside unit, install acleanable strainer at a portion close to the pump piping inlet.5 Carry out complete cooling/thermal insulation of water pipingand outside dehumidification. If complete cooling or thermalinsulation has not been carried out, any damage may becaused during severe winter due to freezing, in addition tothermal loss.6 When you stop operation during night or winter, it is necessaryto take measures to prevent water-related circuits from naturalfreezing in the area the ambient temperature drops below 32°F(0°C) (by water drain off, keeping the circulation pump running,warming up by a heater, etc.) Freezing of water related circuitsmay result in any damage to the plate-type heat exchanger.Therefore, take appropriate measures depending on thecircumstances of use.Before starting a test run1 Before starting a test run, please make sure that the pipingwork has been carried out in a proper manner. Especially, makesure that the strainer, air discharge valve, automatic watersupply valve, expansion tank and cistern are positioned at theirplaces correctly.2 After water has been completely filled in, first run the pumponly, and then make sure that no air has been caught in thewater circulation system and that the water flow rate is correct.If any air has been caught or the flow rate is not enough, theplate-type heat exchanger may freeze. Measure any waterpressure loss before and after the outside unit and make surethat the flow rate is as designed. In case of any abnormality,stop the test run immediately and carry out trouble shooting toresolve the trouble.3 Following the installation manual, carry out a test run of theoutside unit.4 After the test run has been completed, inspect the strainer atthe inlet piping of the outside unit. Clean it if it is dirty.a b c defghia Water inlet pipingb Strainer (accessory)c Air discharge valve (for joint use with cleaning port)d Cleaning devicee Strainer for pump (field supply)f Automatic air discharge valveg Water outlet pipingh Joint use with water draining plugi Plate-type heat exchanger4 4 4 Variable water flow rateThe RWEQ96~144TA* models are equipped with the logic tooperate with a variable water flow rate function.abca Constant flowb Flow regulating valve (field supply)c Inverter pump (field supply)A system can either be configured as a constant flow system (a), avariable flow system with valve (b) or a variable flow system with apump (c).▪ Constant flow system (a): the variable water flow rate function isnot used.▪ A pressure independent flow regulating valve (b): the valvecontrols the flow rate of a centralized inverter pump through theunit.▪ Inverter pump (c): the pump directly controls the water flow ratethrough the unit.To activate the variable flow system, change field setting [2-24] tothe applicable value. See "7.2 Making field settings" on page 35.NOTEMake sure that all field supplied equipment for variableflow rate can be switched off together with the outside unit.This is required when cleaning the plate heat exchanger.NOTE▪ Make sure that all field supplied equipment for variableflow rate meet the minimum hydronic and electricspecifications. Failure to do so can result in inefficientoperation or even breakdown of the system.▪ The outside unit is equipped to deliver variable flowsignal to one hydronic pump. Hence it is recommendedto install only one hydronic pump per single module ofthe system.Size the valve (b) or pump (c) in accordance with the maximumrequired flow rate A, calculated by the installer of the hydronicsystem (with respect to the operation range of the outside unit). Thetypical operation range of the flow rate of the valve/pump is 50% (B)to 100% (A).